US Patent 10405855 Firing circuit for surgical stapler

A surgical instrument includes a stapling head assembly, an anvil, a firing assembly, a motor, a user input feature, and an electrical circuit. The firing assembly actuates the stapling head assembly to drive an annular array of staples through tissue toward the anvil. The motor actuates the firing assembly through an actuation stroke to thereby actuate the stapling head assembly. The electrical circuit includes a trigger switch and an electrical latching feature. The trigger transitions from an open state to a closed state in response to the user input feature transitioning from a non-actuated state to an actuated state. The electrical circuit activates the motor in response to closure of the trigger switch. The electrical latching feature maintains activation of the motor to complete the actuation stroke even if the trigger switch is transitioned back to the open state before completion of the actuation stroke.